Start clutch device

ABSTRACT

A clutch assembly for starting a vehicle without using a torque converter has a simple structure yet providing high reliability. In the clutch assembly ( 1   1   , 1   2   , 1   3 ), a clutch ( 10 ) and a damper device ( 12   1   , 12   2 ) are housed in a housing ( 2 ) connected to a crank shaft of an engine. A boss ( 30 ) serving as an output member is connected to an input shaft ( 28 ) of an automatic transmission. An output of the engine is connected/disconnected to/from the input shaft ( 28 ) upon engagement/disengagement of the clutch ( 10 ). The clutch ( 10 ) includes a friction member ( 14 ) and a piston ( 20 ) fit oil tightly with the housing ( 2 ) so as to apply pressure to the friction member ( 14 ). One end of the damper device ( 12   1   , 12   2 ) is connected to a clutch hub ( 16 ), and the other end is connected to the output member ( 30 ). The clutch ( 10 ) and the damper device ( 12   1   , 12   2 ) are aligned on the axis of the housing ( 2 ).

FIELD OF THE INVENTION

[0001] The present invention relates to a clutch assembly interposed between an engine and an automatic transmission of a vehicle, and more particularly, to a clutch assembly including a clutch and a damper device.

BACKGROUND OF THE INVENTION

[0002] Generally a hydraulic power transmission such as a torque converter and a fluid coupling is employed as a clutch assembly of a vehicle. In the case where the hydraulic power transmission is employed in the vehicle having an internal combustion engine that keeps the drive source in an operating state, even if the vehicle is stopped, the fluid supplied from the hydraulic power transmission allows a relative rotation between an input shaft of the automatic transmission and an output shaft of the engine so as to keep the operation of the drive source. The fluid of the hydraulic power transmission, thus, allows the vehicle to have a smooth take-off and power of the engine is transmitted to the input shaft of the automatic transmission.

[0003] The aforementioned hydraulic power transmission or the torque converter allows the vehicle to have a good automatic take-off performance owing to the relative rotation between the input and output members, and slip function. The required size of the hydraulic power transmission, however, becomes relatively large. This may interfere with reduction in weight and size of the vehicle. As a lock-up clutch is employed to prevent a power loss that generally occurs during power transmission through the fluid, the structure of the hydraulic power transmission may become further complicated. Even if the lock-up clutch is employed for the aforementioned reason, it cannot eliminate all the power loss.

[0004] The demand for the torque converter to increase the torque ratio or provide a shock absorbing function of the fluid upon shifting has been decreased owing to the increase in the shift speeds of the automatic transmission and further development of the continuously variable transmission (CVT). Instead the clutch assembly using no fluid has been proposed in response to the demand for reducing weight and size of the automatic transmission.

[0005] In Japanese Patent Application No. 2001-3955, for example, the clutch assembly has a housing connected to an internal combustion engine, where a multiple disc clutch, a damper device and a one-way clutch are housed therein. When the vehicle is stopped, the multiple disc clutch is connected by a pressure spring so as to generate a predetermined creep force. When the vehicle is about to take off, the multiple disc clutch is engaged under pressure of a piston upon supply of an oil pressure to an oil chamber. The driving force of the engine is then transmitted to the input shaft while the impact being absorbed by the damper device. Further the one-way clutch serves to prevent the vehicle from moving backward upon running uphill.

[0006] The aforementioned clutch assembly has a clutch case serving as an output member and a hub serving as an input member in the housing such that a wet-type multiple disc clutch is formed by interposing a plurality of friction plates between the clutch case and the hub. The piston that presses the clutch is fit oil tightly with the clutch case and an outer race of the one-way clutch via O-rings, respectively. An oil pressure is supplied between the outer race and the clutch case from an oil hole formed in the input shaft to the oil chamber defined by the piston and the clutch case.

[0007] The aforementioned clutch assembly has a housing that constitutes an outer frame of the clutch assembly, in which the clutch case for the clutch is provided as well as the oil chamber. The reaction force of the clutch against the pressure acts on the clutch case, and the force in the axial direction is generated between the housing and the elements housed in the clutch case. In this case, a thrust bearing and the like has to be provided for the purpose of bearing the axial force (thrust). As the oil chamber is defined by the clutch case housed in the housing and the outer race, the oil passage through which the oil pressure is supplied/discharged between the input shaft and the oil chamber requires at least two oil seals interposing the oil hole formed in the input shaft.

[0008] In the generally employed clutch assembly, the oil chamber and the clutch are provided in the clutch case housed in the housing. The structure of the clutch assembly becomes complicated because of the needs for providing the thrust bearing and the oil passage in addition to the clutch case itself, thus degrading reliability of the clutch assembly.

[0009] Additionally, the damper device is disposed on an outer periphery in the radial direction of the multiple disc clutch. As a result, the radial size of the clutch assembly is increased. Especially when two springs for the damper device are provided in the radial direction for improving the damper performance, the radial size of the clutch may further be increased, thus deteriorating ease of mounting the clutch assembly on the vehicle.

[0010] It is an object of the present invention to provide a clutch assembly that allows a vehicle to take off without using a hydraulic power transmission such as a torque converter while having a simple structure in which no oil chamber nor a clutch is disposed in a clutch case housed in a housing, thus improving reliability.

[0011] It is another object of the present invention to provide a clutch assembly that has a reduced radial size so as to improve ease of mounting the clutch assembly on the vehicle.

DISCLOSURE OF THE INVENTION

[0012] In a clutch assembly (1 ₁, 1 ₂, 1 ₃) including a clutch (10) and a damper device (12 ₁, 12 ₂) housed in a housing (2) that is connected to an engine output member, and an output member (30) connected to an input shaft (28) of an automatic transmission, and performing connection and disconnection of an output of an engine fed to the input shaft (28) of the automatic transmission by engaging and disengaging the clutch (10) as claimed in claim 1, the clutch (10) includes a first friction member, a second friction member (14, 13), and a piston (20) that is oil tightly fit with the housing (2) so as to apply pressure to the first and the second friction members; and the damper device (12 ₁, 12 ₂) axially aligned with the clutch (10) has one end connected to a clutch hub (16) that supports the second friction member (13) and the other end connected to the output member (30).

[0013] According to the present invention, the vehicle can be started through transmission of an output of the engine to an input shaft of the automatic transmission by connecting/disconnecting the clutch without using the torque converter (T/C). This makes it possible to eliminate the slip between the input/output members as caused in the case where the T/C is employed, thus improving the transmission efficiency. In the present invention, as an oil chamber is defined by fitting a piston of the clutch oil tightly with the housing, an oil leakage from the oil chamber to the housing can be prevented, further improving controllability of the clutch. The invention provides the clutch assembly having a simple structure by eliminating the clutch case for storing the clutch and the hydraulic actuator, as being separated from the housing, resulting in high reliability. As the damper device is aligned with the clutch with respect to the axial direction, a position of the damper spring can be freely determined in the radial direction of the damper device. This makes it possible to increase the degree of freedom in designing the damper device.

[0014] The clutch assembly as claimed in claim 2 further includes an oil chamber (23) formed between the piston (20) and the housing (2) so as to be overlapped with the first and the second friction members (14, 13) at a side of inner circumferences thereof in an axial direction.

[0015] According to the present invention, as the clutch and the damper device are aligned with respect to the axial direction, the axial length of the housing is increased. However, the oil chamber and the friction members are aligned so as to be overlapped in the axial direction such that the increase in the axial length of the housing can be kept to a minimum value.

[0016] In the clutch assembly as claimed in claim 3, the housing (2) includes a connecting portion (55) connected to the engine output member, a first housing member (5) to which the connecting portion (55) is fixed, and a second housing member (3, 6, 7) connected to the first housing member (5); and the first friction member (14) is fit with a spline (15) formed on the first housing member (5).

[0017] According to the present invention, as the friction members are disposed in the first housing member, the output torque of the engine is not transmitted through a portion at which the first and the second housing members are joined by, for example, welding. As a result, the strength of the housing including a plurality of members can be easily ensured.

[0018] In the clutch assembly as claimed in claim 4, the piston (20) is oil tightly fit with the second housing member (3, 6, 7) for applying pressure to the first and the second friction members (14, 13) upon a supply of an oil pressure to the oil chamber (23) formed between the piston (20) and the second housing member (3, 6, 7).

[0019] According to the present invention, the joint portion of the first and the second housing members is not formed in the oil chamber. This makes it possible to prevent the oil leakage from the oil chamber even if a high hydraulic pressure acts thereon. In the clutch assembly as claimed in claim 5, the damper device (12 ₁, 12 ₂) includes a drive plate (31), a driven plate (33), a first spring (35) functions between the drive plate (31) and the driven plate (33), and a second spring (34) that functions between the drive plate (31) and the driven plate (33) with a predetermined allowance; and the drive plate (31) is connected to the clutch hub (16) and the driven plate (33) is connected to the output member (30).

[0020] According to the present invention, in spite of the first and the second springs disposed for the purpose of damper function, increase in the radial size of the clutch assembly can be prevented since the clutch and the damper device are aligned with respect to the axial direction.

[0021] In the clutch assembly as claimed in claim 6, the damper device (12 ₁, 12 ₂) further includes an intermediate plate (32); and the first spring (35) functions in a serial manner between the drive plate (31) and the intermediate plate (32), and between the intermediate plate (32) and the driven plate (33).

[0022] According to the present invention, the damper stroke is increased by the first and the second springs such that the torque can be transmitted to the driven plate while absorbing the impact acting on the drive plate over the long stroke. This makes it possible to absorb fluctuation in the torque caused by the clutch engagement or the engine operation.

[0023] In the clutch assembly as claimed in claim 7, the first spring (35) is disposed at an inner radial side of the damper device with respect to the second spring (34).

[0024] According to the present invention, the rotational angle becomes greater when the spring is disposed on the inner radial side compared with the spring disposed on the outer radial side. Accordingly the first spring is disposed at the inner radial side so as to obtain the stroke longer than the stroke that is assumed to be obtained when it is disposed at the outer radial side.

[0025] In the clutch assembly as claimed in claim 8, the input shaft (28) of the transmission is assembled with an inner peripheral surface of the output member (30) through a spline; a sleeve shaft (41) is fit with the input shaft (28) with a first gap (a) so as to be fit with the output member (30) oil tightly; a hub (7) constituting the housing (2) is oil tightly and rotatively supported on a transmission case (45) of the transmission with a second gap (b) formed on an outer radial side of the sleeve shaft (41); and the first gap and the second gap (a, b) form a lubricating oil circulation passage in the housing (2).

[0026] According to the present invention including no one-way clutch, there is an oil passage for circulating lubricating oil through which the housing is lubricated in a space at the inner and outer radial sides of the sleeve shaft. This makes it possible to supply the lubricating oil with elements that constitute the clutch and the damper device within the housing. Especially, the oil passage allows supply of the lubricating oil to the space between members that relatively and slidably rotate at the stroke of the damper device, improving supporting accuracy and durability.

[0027] The clutch assembly as claimed in claim 9 further includes a one-way clutch (60) fit into a concave portion (30 g) formed on one side of the output member (30) by fixing an outer race (61) thereto. In the clutch assembly, a sleeve (63 a) is formed on an inner race (63) of the one-way clutch; an input shaft (28) of the transmission is assembled with an inner peripheral surface of the output member (30) through a spline (30 e, 28 b); a sleeve shaft (41) is fit with the input shaft with a first gap (a), and the sleeve (63 a) formed on the inner race is fit with the sleeve shaft so as to be engaged with a spline (63 b, 41 b); a hub (7) constituting the housing (2) is oil tightly and rotatively supported on a transmission case (45) of the transmission with a second gap (b) formed on an outer radial side of the sleeve shaft (41) and the sleeve (36 a); and a communication hole (41 c) is formed on an end of the sleeve shaft (41) such that the first gap and the second gap (a, b) form a lubricating oil circulation passage in the housing (2).

[0028] According to the present invention including the one-way clutch, the lubricating oil can be reliably supplied to the elements stored in the housing, especially, the bearing surface of the connection plate or the drive member, thus improving supporting accuracy and durability.

[0029] In the clutch assembly as claimed in claim 10, the housing (2) includes a side surface (3 c), a hub (3 b), and a cylindrical portion (5 b) which are integrated with the side surface (3 c) thereof; an outer friction plate (14) serving as the first friction member and an inner friction plate (13) serving as the second friction member are engaged with a spline (15) disposed on the inner peripheral side of the cylindrical portion and with a spline (16 a) disposed on an outer peripheral surface of the clutch hub (16), respectively so as to form the clutch (10) of a wet multiple disk type; an oil passage (29 a, 29 b) formed on the hub (3 b) is communicated with an oil chamber (23) defined by a side surface (3 c) of the housing and the piston (20); and the piston (20) serves to apply pressure to the clutch (10), and resultant counter force of the clutch is directly supported by the housing (2).

[0030] According to the present invention, the cylindrical portion and the hub portion do not have to be integrally formed with the housing. Alternatively welding of the cylindrical portion (clutch drum) and/or the hub portion to the housing may be performed so as to form the spline on the inner peripheral surface of the clutch drum.

[0031] The clutch assembly according to the present invention requires no clutch case for the clutch and the hydraulic actuator as being formed separately from the housing. The resultant structure can be simplified. The reaction force resulting from the pressure applied by the clutch acts on the side surface that constitutes the oil chamber, and the cylindrical portion with which the outer friction plate is engaged in the opposite directions, respectively. Such reaction force can be absorbed by the housing, thus requiring no thrust bearing that bears the reaction force against the clutch, further simplifying the structure of the clutch assembly. The oil pressure is supplied to the oil chamber and then discharged therefrom through the oil passage formed on the hub portion of the housing. The structure of the oil passage, thus, can be simplified. As a result, the size and weight of the clutch assembly can be reduced, and reliability thereof can be improved.

[0032] In the clutch assembly as claimed in claim 11, the cylindrical portion is an intermediate cylindrical portion (5 b) that is formed on an intermediate portion to the front of the housing (2) in the radial direction; the side surface (3 c) of the housing is formed of a flat plate-like member that is disposed on an inner radial side of the intermediate cylindrical portion (5 b); and the damper device (1 ₁, 1 ₂) is stored in a large-diameter storage portion (A) formed to the rear (6, 5 c, 5 d) of the housing (2), and a hydraulic actuator (11) formed of the clutch (10), the piston (20), and the oil chamber (23) is disposed in a small-diameter storage portion (B), and formed on an inner radial side of the intermediate cylindrical portion (5 b) to the front (3, 5 a, 5 b) of the housing (2).

[0033] According to the present invention, the damper device is stored in the large-diameter storage portion, to the rear of the housing, and the clutch and the hydraulic actuator are disposed at the inner radial side of the intermediate cylindrical portion to the front of the housing. The impact caused by connection of the clutch can be absorbed with high efficiency by the damper device having a large-diameter such that the torque can be smoothly transmitted to the input shaft. Additionally, the heavy load for fly-wheeling effect or the motor-generator for a hybrid vehicle (including idling stop system) can be disposed in a hollow space formed at the outer radial side of the intermediate cylindrical portion.

[0034] In the clutch assembly as claimed in claim 12, a retainer plate (25) is fixed to the hub (3 b) of the housing (2), and a return spring (26) is disposed under pressure between the retainer plate (25) and a back surface of the piston (20).

[0035] According to the present invention, the retainer is fixed to the hub portion of the housing, and the return spring is disposed under pressure between the retainer and the back surface of the piston. The reaction force of the return spring can be absorbed by the housing. The clutch assembly of the present invention, thus, requires no bearing of the reaction force or the thrust force. As a result, the structure of the present invention can be simplified as well as the reliability is improved.

[0036] In the clutch assembly as claimed in claim 13, the spline (15) used for engaging the outer friction plate (14) of the clutch (10) is directly formed on an inner peripheral surface of the cylindrical portion (5 b) in the housing (2).

[0037] According to the present invention, the spline for the outer friction plate is directly formed on the inner peripheral surface of the cylindrical portion of the housing. As a result, the clutch drum is not required, thus reducing the size and weight in the clutch assembly.

[0038] In the clutch assembly as claimed in claim 14, a concave portion (3 d) is formed on an end surface of the hub (3 b) of the housing (2) such that the input shaft (28) of the transmission is oil tightly fit (27) with the concave portion; and an oil hole (28 a) that extends in an axial direction is formed in the input shaft, and an end opening of the oil hole is communicated with the oil passage (29 a, 29 b) formed in the hub (3 b).

[0039] According to the present invention, the opening of the end of the oil hole formed in the input shaft is communicated with the oil passage of the hub portion. Unlike the generally employed clutch assembly having the sealing devices at the right and left of the oil passage, the present invention requires only a single sealing device such as the O-ring for forming the oil passage, which is interposed between the hub portion and the input shaft. This makes it possible to reduce the cost and to improve reliability of the structure of the oil passage.

[0040] In the clutch assembly as claimed in claim 15, the piston (20) has an operating portion (20 c) that extends toward an outer radial direction such that the clutch is operated; and the operating portion (20 c ₂) abuts on an inner surface of the housing upon disengagement of the clutch (10), and has an outer circumference (20 c ₁) engaged with a spline (15) on an inner peripheral side of the cylindrical portion.

[0041] According to the present invention, the operating portion abuts on the inner surface of the housing in the state where the piston is operated. The entire area of the surface of the piston serves as the pressure bearing area upon start of supply of the oil pressure to the oil chamber. This makes it possible to start operating the piston quickly. The outer peripheral surface of the piston operating portion is engaged with the spline at the inner circumference of the cylindrical portion so as to be locked. This makes it possible to eliminate the device for locking the piston, thus simplifying the structure of the clutch assembly.

[0042] In the clutch assembly as claimed in claim 16, the clutch (10) includes at least one friction plate (14) comprising the first friction member that is engaged with a spline (15) for rotating integrally with the housing (2), and at least one inner friction plate (13) comprising the second friction member that is engaged with a spline (16 a) formed on a clutch hub (16), which are alternately disposed; the damper device (12 ₁, 12 ₂) includes a drive member (31 or 33, 32), a driven member (33 or 32), and a spring (34, 35) disposed on a power transmission path from the drive member to the driven member; the damper device further includes a boss (30) serving as the output member connected to the driven member, and an input member (36 or 16 b) integrally combined with the clutch hub and connected to the drive member; and an inner peripheral surface of the input member is slidably supported directly on an outer peripheral surface (30 a) of the boss in a rotating direction while being restricted with respect to an axial movement.

[0043] The aforementioned drive member corresponds to the one at the drive side with respect to the driven member connected to the boss serving as the output member. In the case where the impact is absorbed in multiple stages from at least one drive plate to the intermediate plate, the intermediate plate may be regarded as the drive member as well as the drive plate.

[0044] The present invention makes it possible to use the damper device having a high impact absorption efficiency over a long stroke (long travel) by connecting the clutch hub of the clutch and the drive member of the damper device via the input member. As the input member is directly supported on the outer peripheral surface of the boss serving as the output member while being restricted with respect to the axial movement, it may be supported on the simple structure without the bush or the bearing. This makes it possible to reduce the size and weight of the clutch assembly. The input member integrally formed with the clutch hub rotates together with the boss at a time other than the moment of the stroke (travel) of the damper device. Accordingly, the period taken for the relative sliding motion between the input member and the boss is substantially short. In other words, they rotate synchronously most of the time. As a result, degradation of the supporting accuracy owing to the wear at the earlier stage can be prevented, improving durability and reliability.

[0045] In the clutch assembly as claimed in claim 17, the input member (36 or 16 b) has a cylindrical hub portion (36 b, 16 c) on an inner peripheral surface thereof; the boss (30) includes a cylindrical support portion (30 a) that supports the hub portion, a protruding portion (30 b or 30 g) formed on one end of the support portion (30 a) in an axial direction and, protruding toward an outer radial direction, and a restricting member (33 a, 75, 76) formed on the other end of the support portion in the axial direction and, protruding toward an outer radial direction of the support portion while being restricted with respect to at least a movement in the axial direction; and the input member (36 or 16 b) is slidably supported on the support portion (30 a) of the boss (30) and interposed between the protruding portion (30 b or 30 g) and the restricting member (33 a, 75, 76) so as to be restricted with respect to the movement in the axial direction.

[0046] According to the present invention, the input member is supported on the support portion of the boss with the cylindrical hub portion. As it is supported by a relatively large area of the support portion, and restricted with respect to the axial movement by the protruding portion and the restricting portion formed on the boss, the input member is stably supported by preventing tilting and the like. Although one end of the boss is integrally formed with the protruding portion, the other end can be removed from the restricting member. This makes it possible to support the hub portion of the input member easily with high accuracy, simplifying the assembly and maintenance.

[0047] In the clutch assembly as claimed in claim 18, the protruding portion (30 b or 30 g) of the boss (30) is a collar portion (30 a) integrally formed with the cylindrical support portion, and the restricting member is an extending portion (33 a) of the driven member fixed at the boss.

[0048] According to the present invention, the boss has the collar portion at one end of the support portion, and the extending portion of the driven member is fixed to the other end of the support portion. As the axial movement of the input member is restricted by the collar portion and the extending portion, the device for supporting the input member is not required. The aforementioned collar portion directly formed on the boss and the extending portion directly fixed to the boss make it possible to simplify the structure and to provide the high support accuracy.

[0049] In the clutch assembly as claimed in claim 19, the input member (36 or 16 b) is a connection plate (36) that serves to fix the clutch hub (16), extends in a radial direction to be connected to the drive member (31) on an outer radial portion thereof, and forms the hub portion (36 b) on an inner radial portion thereof.

[0050] According to the present invention, the drive member of the damper device and the clutch hub are connected with the connection plate. The connection plate is then supported with the boss. The damper device may be used to input the torque from the outer radial side so as to be output from the inner radial side in the usual mode, while supporting the connection plate with sufficient durability.

[0051] In the clutch assembly as claimed in claim 20, the driven member (33) is formed of two driven plates (33) that interpose the drive member (31, 32) and the spring (34, 35); at least one of the two driven plates is fixed to the boss (30); and an inner peripheral surface of the drive member (32) is slidably supported directly on an outer peripheral surface of a ring portion (37, 61 a) integrally formed with the boss.

[0052] According to the present invention, the ring portion is not limited to the one as shown in FIG. 1. It may be formed as one of function parts to be structured as the outer race of the one-way clutch as shown in FIG. 2.

[0053] In the present invention, the drive member of the damper device is directly supported on the ring portion integrally formed with the boss. So the damper device can be supported by the simple structure with the reduced size and weight. The period taken for the relative rotation between the input and the output members is substantially short, thus providing sufficient durability and reliability.

[0054] In the clutch assembly as claimed in claim 21, the damper device (12 ₁, 12 ₂) includes a drive plate (31 or 33), an intermediate plate (32), a driven plate (33 or 31), a first spring (35) functioning in a serial manner between the drive plate and the intermediate plate, and between the intermediate plate and the driven plate, respectively, and a second spring (34) functioning between the drive plate and the driven plate with a predetermined allowance; and the drive plate (31 or 33) is formed of the drive member connected to the input member (36 or 16 b), and the intermediate plate (32) is formed of the drive member supported on the ring portion (37, 61 a, 30 g).

[0055] According to the present invention, the damper device has the long stroke (travel) owing to the first spring that functions in the serial manner via the intermediate plate. The second spring serves to change the load for absorption in the middle of the stroke. Those first and the second springs allow efficient and smooth absorption of the fluctuation in the torque caused by connection of the clutch, resulting in the smooth take-off.

[0056] In the clutch assembly as claimed in claim 22, the ring portion (61 a) is formed on an outer race (61) of a one-way clutch (60) disposed in a concave portion (30 g) of the boss (30) so as to protrude toward an outer radial direction.

[0057] The present invention makes it possible to prevent the vehicle that is stopped uphill from being moved backward (to provide the hill-holding effect) by means of the one-way clutch.

[0058] In the clutch assembly as claimed in claim 23, the protruding portion (30 k) of the boss (30) is a connecting portion (30 j) of the driven member integrally formed with the boss, and the restricting member is a lock member (75, 76) that is fixed to the support portion.

[0059] According to the present invention, the axial movement of the boss is restricted by the joint portion of the driven member integrally formed with the boss, and the lock member such as the snap ring. The member integrated with the clutch hub may be supported on the supporting portion of the boss, simplifying the assembling work.

[0060] In the clutch assembly as claimed in claim 24, the input member is a clutch hub integrated member (16 b) that is integrally formed with the clutch hub (16), and connected to the drive member (33) on an inner radial portion so as to form the hub portion (16 c).

[0061] According to the invention, the input member is formed integrally with the clutch hub, and connected to the drive member at the inner radial side. This makes it possible to simplify the structure for connecting the clutch and the damper device, reducing the size of the clutch assembly in the axial direction.

[0062] In the clutch assembly as claimed in claim 25, the drive member (33) is formed of two drive plates (33) that interpose the driven member (31) and the spring 34, 35); one of the two drive plates which locates at the clutch hub (16) is fixed to the clutch hub integrated member (16 b); a connection plate (73) that extends toward a radial direction is provided so as to connect the driven member (31) and the boss (30); and an inner peripheral surface of the drive member (32) is slidably supported on an outer peripheral surface (30 g) of the ring portion (30 f) integrally combined with the boss (30).

[0063] According to the present invention, the drive member of the damper device is directly supported on the ring portion integrated with the boss. The damper device, therefore, may be supported by the simple structure with reduced size and weight. The period taken for the relative rotation between the input and the output members is substantially short, thus providing sufficient durability and reliability.

[0064] In the clutch assembly as claimed in claim 26, the damper device (12 ₁, 12 ₂) includes a drive plate (31 or 33), an intermediate plate (32), a driven plate (33 or 31), a first spring (35) functioning in a serial manner between the drive plate and the intermediate plate, and between the intermediate plate and the driven plate, respectively, and a second spring (34) functioning between the drive plate and the driven plate with a predetermined allowance; and the drive plate (31 or 33) is formed of the drive member connected to the input member (36 or 16 b), and the intermediate plate (32) is formed of the drive member supported on the ring portion (37, 61 a 30 g).

[0065] According to the present invention, the damper device has the long stroke (travel) owing to the first spring that functions in the serial manner via the intermediate plate. The second spring serves to change the load for absorption in the middle of the stroke. Those first and the second springs allow efficient and smooth absorption of the fluctuation in the torque caused by connection of the clutch, resulting in the smooth take-off.

[0066] In the clutch assembly as claimed in claim 27, the ring portion (61 a) is formed on an outer race (61) of a one-way clutch (60) disposed in a concave portion (30 g) of the boss (30) so as to protrude toward an outer radial direction.

[0067] The present invention makes it possible to prevent the vehicle that is stopped uphill from being moved backward (to provide the hill-holding effect) by means of the one-way clutch.

[0068] In the clutch assembly as claimed in claim 28, the housing (2) has a large-diameter storage portion (A) on one side, and a small-diameter storage portion (B) on the other side; and the large-diameter storage portion (A) stores the damper device (12 ₁, 12 ₂) and the input member (36, 16 b), and the small-diameter storage portion (B) stores the clutch (10) and a hydraulic actuator (11).

[0069] According to the present invention, the damper device with the large radial size and high performance may be stored in the large-diameter storage portion of the housing so as to absorb the impact caused by connection of the clutch. In the present invention, the clutch and the actuator are disposed in the small-diameter storage portion of the housing such that a hollow space is formed at the outer radial side of the small-diameter storage portion. The heavy load for fly-wheeling effect or the motor-generator for a hybrid vehicle (including idling stop system) can be disposed in the hollow space.

[0070] A clutch assembly (1 ₁, 1 ₂, 1 ₃) as claimed in claim 29 includes a clutch (10) and a damper device (12 ₁, 12 ₂) housed in a housing (2) that is connected to an engine output member, and an output member (30) connected to an input shaft (28) of an automatic transmission and having both sides directly supported on the housing (2) via a bearing (39, 40), and a take-off controller that transmits an output of the engine to the automatic transmission by engaging the clutch (10) so as to start a vehicle. In the clutch assembly, the damper device (12 ₁, 12 ₂) includes a drive plate (31) connected to an output member (16) of the clutch, a driven plate (33) connected to the output member (30), a first spring (35) functioning in a serial manner between the drive plate (31) and the driven plate (33), and a second spring (34) functioning between the drive plate (31) and the driven plate (33) with a predetermined allowance, and the first spring (35) is disposed at an inner radial side of the damper device with respect to the second spring (34); and the damper device (12 ₁, 12 ₂) including the first and the second spring (35, 34) arranged in the radial direction is aligned with the clutch (10) in an axial direction.

[0071] In the clutch assembly, the clutch and the damper device are aligned in the axial direction. This makes it possible to prevent the clutch assembly from becoming unnecessarily large-sized in the radial direction in spite of the first and second springs disposed for providing damper function. The resultant mountability of the clutch assembly to the vehicle, thus, may be improved.

[0072] The reference numerals are used only for referring to the drawings for understanding of the present invention. It is to be understood, therefore, that the scope of the invention is to be determined soley by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0073]FIG. 1 is a sectional view of a clutch assembly to which the present invention is applied, in which no one-way clutch is provided;

[0074]FIG. 2 is a sectional view of a clutch assembly to which the present invention is applied, in which a one-way clutch is provided;

[0075]FIG. 3 is a partial broken view representing the front of a damper device of the clutch assembly; and

[0076]FIG. 4 is a sectional view of a clutch assembly that has been partially modified.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0077] An embodiment of the present invention will be described referring to the drawings. FIG. 1 shows a clutch assembly with no one-way clutch. FIG. 2 shows a clutch assembly with a one-way clutch. FIG. 4 shows a clutch assembly as a modified embodiment in which an input or a drive member and an output or a driven member of the damper device are reversed. The clutch assembly is connected to an internal combustion engine such as a gasoline engine to the right of the drawings, and connected to an automatic transmission, for example, a CVT, an automatic transmission with multiple speeds (6 forward speeds and 1 reverse speed) and the like to the left of the drawings. The clutch assembly has a clutch controller that engages the clutch 10 (described later) to transmit outputs of the engine to the automatic transmission such that the vehicle takes off.

[0078] Referring to FIG. 1, a clutch assembly 1 ₁ includes a housing 2 that forms an outer frame of the clutch assembly 1 ₁. The housing 2 is formed by bonding a center piece 3, a front cover 5, a rear cover 6 and a rear hub 7 altogether by welding and the like. The center piece 3 and the front cover 5 are bonded at a welded point j 1. The front cover 5 and the rear cover 6 are bonded at a welded point j2. The rear cover 6 and the rear hub 7 are bonded at a welded point j3. The front cover 5 constitutes a first housing member. The center piece 3, the rear cover 6 and the rear hub 7 constitute a second housing member.

[0079] The center piece 3 includes a protruding portion 3 a that fits with a crank shaft (not shown) or an engine output member of the engine, a hub 3 b, and a disc portion (front side surface) 3 c having a flat surface extending toward the outer radial direction. The front cover 5 includes a front side surface 5 a welded to an outer peripheral surface of the disc portion 3 c, an intermediate cylindrical portion 5 b that bends at substantially 90 degrees with respect to the front side surface 5 a and extends in an axial direction, a bent portion 5 c that bends at substantially 90 degrees with respect to the rear end portion of the cylindrical portion toward the outer radial direction, and an outer peripheral portion 5 d that extends in substantially an axial direction from an outer periphery of the bent portion 5 c. The rear cover 6 is welded to an end of the outer peripheral portion 5 d of the front cover 5, and includes a rear side surface 6 a formed into an arm-like shape. The rear hub 7 includes a disc portion 7 a welded to an inner periphery of the rear surface 6 a, and a cylindrical portion 7 b that bends at 90 degrees with respect to the inner periphery of the disc portion 7 a, and extends in the axial direction. The intermediate cylindrical portion 5 b may be separated from the front cover such that they are joined by welding.

[0080] A clutch 10 and a damper device 12 ₁ are housed in the housing 2. The clutch 10 includes a wet-type multiple disc clutch in which a plurality of clutch plates (first friction members) 14 and clutch discs (second friction members) 13 are alternately disposed in the axial direction, and a hydraulic actuator 11 including a piston 20 (to be described later) and a cylinder for operating the clutch. A spline 15 is directly formed on the inner peripheral surface of the intermediate cylindrical portion 5 b of the front cover 5. The spline 15 is brought into engagement with the clutch plates 14 as the outer friction plates so as to be fastened with a snap ring 14 a. A cylindrical clutch hub (clutch output member) 16 is disposed at an inner diameter side of the intermediate cylindrical portion 5 b. A spline 16 a formed on the outer peripheral surface of the clutch hub 16 is engaged with the clutch discs 13 as inner friction plates. In this embodiment, the spline 15 is directly formed on the inner peripheral surface of the intermediate cylindrical portion 5 b so as to form a clutch drum directly on the front cover 5. However, the clutch drum as being a separate element may be welded to the front cover 5 into one body.

[0081] The center piece 3 has an annular groove 17 on an outer circumference of the disc portion 3 c located inside of the front cover 5, and an annular groove 19 on an outer circumference of the hub portion 3 b. The piston 20 is oil tightly fit with the aforementioned annular grooves 17, 19 via O-rings 21, 22, respectively. An oil chamber 23 that constitutes the hydraulic actuator 11 is defined by the piston 20 and the cylinder including the disc portion 3 c and the hub portion 3 b. The oil chamber 23 defined by the piston 20 and the housing 2 is disposed so as to be overlapped with the clutch plates 14 and the clutch discs 13 in the axial direction at the inner peripheries (inner radial side) thereof. The piston 20 has a collar 20 a that protrudes such that the inner periphery (inner radial side) thereof locates rearward in the axial direction (at the transmission side, inward of the housing). The O-ring 22 is slidably in contact with the inner peripheral surface of the collar 20 a. The piston 20 further has an outer periphery bent to protrude frontward in the axial direction (at the engine side, outward of the housing). The O-ring 21 is slidably in contact with the inner peripheral surface of the cylindrical portion 20 b. The oil chamber 23 may be defined by the piston 20, the disc portion 3 c, the hub portion 3 b, and the intermediate cylindrical portion 5 c.

[0082] The piston 20 extends to constitute a clutch operating portion. An end 20 c ₁ of a projecting portion 20 c as the clutch operating portion is engaged with the spline 15 such that the piston is locked. The projecting portion 20 c has a protrusion 20 c ₂ in the intermediate portion that abuts against the inner peripheral surface of the front surface 5 a of the front cover 5. As a result, the position where the piston 20 makes a thrust (clutch is disengaged) is determined. As there is no projecting portion for the aforementioned positioning in the oil chamber 23 of the piston 20, the whole surface of the piston in the oil chamber 23 becomes an effective area to bear the pressure upon start of the oil pressure supply from the position where the piston is retracted. This makes it possible to start operation of the piston quickly. The projecting portion 20 c has a hole 20 d for discharging oil, and a concave groove 20 e.

[0083] A retainer plate 25 is fastened to the hub portion 3 b of the center piece 3 with a snap ring. A return spring 26 is set under pressure between the retainer plate 25 and the back surface of the piston 20. The center piece 3 has a concave portion 3 d formed at the side of the hub portion 3 b such that an input shaft 28 of the automatic transmission is fit in the concave portion 3 d. The input shaft has an oil hole 28 a formed therethrough in the axial direction. The oil hole 28 a is opened at the end of the input shaft. An O-ring 27 as a sealing device is fit between the input shaft and the concave portion 3 d of the center piece 3.

[0084] The center piece 3 has an oil hole 29 a that pierces therethrough from the concave portion 3 d and an oil hole 29 b that is formed between the oil hole 29 a and a corner of the hub portion 3 b such that a hydraulic pressure from the oil hole 28 a formed in the input shaft 28 is introduced from the opening of the oil hole 28 a into the oil chamber 23 via the oil holes (oil passages) 29 a, 29 b. In this case, as the opening of the oil hole 28 a of the input shaft is led to the oil hole 29 a formed in the center piece 3, only one O-ring 27 between the input shaft 28 and the center piece 3 is required. As a result, the blocked portion of the center piece requires no sealing device, thus simplifying the structure of the oil passage.

[0085] Meanwhile, a boss 30 serving as an output side of the clutch assembly 1 ₁ (output member) is spline coupled with the input shaft 28, and a damper device 12 ₁ is housed in a large-diameter storage portion A defined by the bent portion 5 c and the rear cover 6 at the outer radial side of the boss 30. The clutch 10 including the hydraulic actuator 11 is stored in a small-diameter storage portion B at the inner radial side of the intermediate cylindrical portion 5 b of the front cover. The damper device 12 ₁ has a drive plate 31, an intermediate plate 32, two driven plates 33, and two kinds of coil springs 34, 35 located on different radial positions, respectively such that the drive plate and the intermediate plate are interposed between the driven plates.

[0086] The large-diameter storage portion A to the front of the damper device 12 ₁ has a connection plate (input member) 36 therein. The connection plate 36 has an annular disc-like shape and is integrally formed with the clutch hub 16 through welding on the outer surface near the center. The outer periphery of the connection plate 36 is axially bent into a collar, on which a comb-like notch 36 a is formed. The connection plate 36 is connected to the drive plate 31 by engaging the notch 36 a with the outer periphery 31 a having concave/convex surface of the drive plate 31. The inner periphery of the connection plate 36 constitutes a cylindrical hub portion 36 b that is slidably supported on the outer periphery 30 a of the boss 30. An extending portion 33 a of the driven plate 33 is held by a ring member (ring portion) 37 so as to be integrally fixed with a rivet 38 to the boss 30. A collar (protruding) portion 30 b that protrudes toward outer radial direction is formed to the front of the outer periphery of the boss 30. The axial orientation of the hub portion 36 b of the connection plate 36 is defined between the collar portion 30 b and the extending portion 33 a. That is, the connection plate 36 abuts on the outer periphery (support portion) 30 a of the boss 30 and is supported by the extending portion 33 a (restricting member) of the driven plate and the collar portion 30 b that restricts its axial movement. The ring member 37 fixed to the boss has a short collar portion 37 a on the outer periphery. The inner periphery of the intermediate plate 32 abuts on the collar portion so as to support the intermediate plate 32 and the drive plate 31.

[0087] The boss 30 has a protrusion 30 d that is formed on the side surface of the intermediate portion and protrudes rearward. A thrust bearing 39 is interposed between the protrusion 30 d and the rear side surface 7 a of the rear hub 7. Further a thrust bearing 40 is interposed between the front side surface of the boss 30 and the rear side surface of the hub portion 3 b of the center piece 3. Those thrust bearings 39, 40 serve to restrict the axial movements of the boss 30, the damper device 12 ₁ that is integrally formed thereto, and the connection plate 36 that is supported by the boss 30 that restricts its axial movement so as to be supported.

[0088] A spline 30 e formed in the inner periphery of the boss 30 is engaged with the spline 28 b formed in the input shaft 28. Therefore the boss 30 serving as the output member is connected to the input shaft 28 of the automatic transmission, having both sides directly supported by the housing 2 via the thrust bearings 39, 40, respectively. A sleeve shaft 41 having a predetermined gap a is supported by the input shaft 28 via a bush 42. A tip end of the sleeve shaft 41 is oil tightly fit with a hub portion 30 f of the boss via an O-ring 43. A cylindrical portion 7 b of the rear hub 7 is disposed at an outer radial side of the sleeve shaft 41 in the presence of a predetermined gap b. The cylindrical portion 7 b is rotatively supported on a transmission case 45 via a bush 46. The portion defined by the transmission case 45 and the cylindrical portion 7 b is oil tightly sealed with an oil seal 47. A portion of the sleeve shaft 41 in contact with the bush 42 has a plurality of concave grooves 49 extending in the axial direction.

[0089] Accordingly a first oil passage is formed between the sleeve shaft 41 and the input shaft 28 for communicating the oil passage within the transmission case and the housing of the clutch assembly, which is defined by the gap a, the concave grooves 49, and the spline 30 e or 28 b having its tooth partially cut. Meanwhile a second oil passage is formed of the gap b between the sleeve shaft 41 and the cylindrical portion 7 b of the rear hub. This makes it possible to form a structure of the lubricating oil passage where the lubricating oil from the transmission case 45 is supplied from one of the first and the second oil passages into the housing 2, and the lubricating oil is then discharged from the other oil passage. The supplied lubricating oil lubricates the thrust bearings 39, 40, the clutch 10, the damper device 12 ₁ and the like within the housing 2, and then discharged. In this case, portions between the outer peripheral surface 30 a of the boss that functions as a surface to support the connection plate 36 and the inner peripheral surface 36 b of the hub, and the collar portion 37 a of the ring member that functions as the surface for supporting the intermediate plate 32 are sufficiently lubricated.

[0090]FIG. 3 is a partial broken view representing the front of the damper device 12 ₁ (12 ₂). The drive plate 31 formed into a ring shape has a concave-convex portion 31 a formed on the outer periphery so as to be engaged with the connection plate 36. The drive plate 31 has a protruding portion 31 b formed on the inner periphery, which extends toward the inner radial direction. The ring shaped portion of the drive plate 31 has a hole 31 c that stores a coil spring (second spring) 34 with small diameter to which a predetermined pressure is applied. The intermediate plate 32 has a protruding portion 32 a that extends toward the outer radial direction on its outer periphery. A first spring 35 formed of two coil springs are set under pressure between the protruding portions 31 b and 32 a. The driven plates 33 disposed on both sides of the drive plate 31 and the intermediate plate 32 and are connected and fixed to those plates 31, 32 with a pin 52 have spring housings 33 c, 33 d that store the first spring 35 and the second spring 34, respectively. A first spring housing 33 c has a length enough to store two adjacent first springs 35. A second spring housing 33 d has a length enough to include a predetermined allowance with respect to the second spring 34.

[0091] Therefore, in the damper device 12 ₁, the rotation of the drive plate 31 is transmitted to the protruding portion 32 a while applying the pressure force to the first spring 35 from the protruding portion 31 b. The rotation transmitted to the protruding portion 32 a of the intermediate plate 32 is further transmitted to the driven plate 33 via the spring housing 33 c while applying the pressure force to the adjacent first spring 35. Those two first springs 35 as being serially arranged are operated via the intermediate plate 32 such that the rotation is transmitted to the driven plate 33 while absorbing the impact acting on the drive plate 31 over a long stroke (long travel).

[0092] A predetermined relative rotation between the drive plate 31 and the driven plate 33 caused by the two first springs 35 as being serially arranged serves to absorb the allowance between one end of the spring housing 33 d and the second spring 34. Then the rotation of the drive plate 31 is transmitted to the driven plate 33 while applying pressure to the second spring 34 at the end of the housing. In addition to absorption of the predetermined torque upon compression of the first spring 35, the impact can be absorbed in the middle of the stroke with a greater resistance upon exertion of the compressive deforming force of the second spring 34. Each of the damper device 12 ₁, 12 ₂ has the intermediate plate 32 such that the first springs 35 act on the portions between the drive plate 31 and the intermediate plate 32, and between the intermediate plate 32 and the driven plate 33. The first and the second springs 35, 34 make it possible to increase the damper stroke so as to absorb the impact to the drive plate 31 over a relatively longer stroke upon transmission of the rotation to the driven plate 33. This makes it possible to absorb fluctuations in the torque owing to the engine operation or upon engagement of the clutch 10. In this embodiment, the stroke established by placing the first springs 35 to be on the inner radial side with respect to the second spring 34 may become longer than the stroke established by placing the first springs 35 on the outer radial side. This is because the resultant rotational angle becomes relatively greater when the spring is disposed on the inner radial side compared with the spring disposed on the outer radial side.

[0093] The clutch assembly 1 ₁ according to the invention will be described. In the state where the vehicle is stopped, the oil pressure within the oil chamber 23 is released, the piston 20 is in a return position where the protruding portion 20 _(c2) is brought into abutment on the front cover 5 by the return spring 26, and the clutch 10 is disengaged. In the aforementioned state, the housing 2, connected to the internal combustion engine, rotates along with the rotation of the engine. As the clutch 10 is disconnected, the rotation of the engine is not transmitted to the clutch hub 16. The input shaft 28 is, thus, in a stopped state. A predetermined low oil pressure may be applied to the oil chamber 23 in order to bring the clutch 10 into a slip state such that the creep torque is applied to the input shaft 28.

[0094] When a takeoff signal is output upon depression of the accelerator pedal by the vehicle operator, the valve (not shown) is operated so as to supply a predetermined oil pressure to the oil hole 28 a of the input shaft 28. The oil pressure is then supplied to the oil chamber 23 through the oil holes 29 a, 29 b. This allows the piston 20 to move against the return spring 26, and its projecting portion 20 c serves to press the clutch plates 14 and the clutch discs 13 to engage the clutch 10. At this moment, the reaction force of the clutch caused by the oil pressure acting on the oil chamber 23 directly acts on the disc portion 3 c of the housing that forms the oil chamber, and the intermediate cylindrical portion 5 b as the force in the opposite direction via the back-up plate 14 b and the snap ring 14 a. The reaction force, therefore, is absorbed within the housing 2 directly without acting on the members other than the clutch assembly.

[0095] Upon engagement of the clutch 10, the rotation of the housing 2 is transmitted to the damper device 12 ₁ via the clutch hub 16 and the connection plate 36. The two adjacent first springs 35 arranged in series on the inner radial side serve to absorb the impact caused by the engagement of the clutch 10 over a long stroke. In the middle of the long stroke, the second spring 34 disposed on the outer radial side serves to absorb further impact. The rotation is then transmitted to the driven plate 33, and further to the input shaft 28 from the boss 30 that is integrally combined with the driven plate 33. The damper device 12 ₁ having a larger radial size is stored in the large-diameter storage space A of the housing 2. The impact absorption over the long travel performed by the first springs 35 arranged in series, and the increase in the load of impact absorption performed by the second spring 34 in the middle of such long stroke make it possible to enhance the effect of absorbing the impact load exerted by the clutch 10.

[0096] When the torque is brought into the steady state after the impact absorption, the springs 34, 35 of the damper device 12 ₁ are released from the compression deformation to the normal states such that the rotation is transmitted in a substantially uniform condition. In this case, the hub portion 36 b of the connection plate 36 is axially oriented so as to be supported on the outer periphery 30 a of the boss 30. During the stroke traveling where the impact is absorbed by the damper device, the outer periphery 30 a rotates relatively to the hub portion 36 b along with the relative rotations between the drive plate 31 and the driven plate 33. In the normal rotating state, however, the hub portion 36 b and the outer periphery 30 a substantially rotate in an integrated manner. Accordingly, the connection plate 36 is supported on the outer periphery 30 a of the boss for most of the times. The connection plate 36 does rotate relative to the outer periphery 30 a at a time of the impact absorption performed by the damper device. However, as the period taken for the relative rotation is rather short, and the aforementioned relative rotation is performed in a sufficiently lubricated condition, the connection plate 36 can be supported with no problems.

[0097] Likewise, the intermediate plate 32 is supported on the ring member 37 integrated with the boss 30. As the stroke and the stroke time of the intermediate plate 32 is shorter than that of the drive plate 31, that is, the connection plate 36 integrated therewith and the relative rotation is performed in a sufficiently lubricated condition, those plates 32, 31 can be supported with no problems.

[0098] A space C is defined by the cylindrical portion 5 b and the outer periphery 5 d of the front cover 5 in the housing 2. The space C is blocked by welding a lid member 55 to the front cover 5. A flexible plate is connected to a screw hole 55 a such that the lid member 55 is connected to the internal combustion engine. The space C may be held in a hollow state. Alternatively, a predetermined load may be filled in the space C in case of necessity so as to enhance the fly-wheeling effect of the housing 2. A motor-generator may be mounted in the space C so as to be employed as the drive unit for a hybrid vehicle (including an idling stop control). A ring gear 56 employed for an engine start-up device is also provided as shown in the figure.

[0099] A clutch assembly 1 ₂ including a one-way clutch according to another embodiment will be described referring to FIG. 2. This embodiment is substantially the same as the embodiment as described above except that the one-way clutch is provided. As other elements are the same as those of the above-described embodiment, the main elements are designated as the reference numerals that are the same as those of the embodiment. The descriptions of those elements, thus, will be omitted.

[0100] The rear portion of the boss 30 that supports the connection plate 36 is deeply cut, and the concave portion 30 g receives a one-way clutch 60. An inner peripheral surface of an inner peripheral hub portion 30 f is engaged with the input shaft 28 with splines 30 e, 28 b. The one-way clutch 60 includes an outer race 61, a sprag 62, an inner race 63, and left and right side plates 65, and is positioned such that the outer race 61 is fit within the concave portion 30 g of the boss 30.

[0101] Like the ring member 37 in the aforementioned embodiment, the rear portion of the outer race 61, that is, a ring extending portion (ring portion) 61 a extending toward the outer radial direction is fixed to the boss 30 together with the extending portion 33 a of the driven plate by the rivet 38. The outer periphery of the ring extending portion 61 a has a collar shape, which abuts on the intermediate plate 32 so as to be supported. The inner race 63 has a sleeve 63 a with the inner circumference axially extending. The inner peripheral surface of the sleeve 63 a is fit with the sleeve shaft 41 and engaged with splines 63 b, 41 b. Meanwhile, the boss 30 has a collar (protrusion) 30 a on a tip end of the outer peripheral surface (supporting portion) 30 a. The hub 36 b of the connection plate 36 is slidably supported on the outer peripheral surface, and is sandwitched between the collar portion 30 a and the extending portion 33 a of the driven plate so as to be supported and restricted with respect to its axial movement.

[0102] The sleeve shaft 41 has a hole 41 c through which the input shaft 28 is communicated with the gap a of the sleeve shaft 41, and the sleeve shaft 41 and the gap c of the sleeve 63 a. This makes it possible to form a first oil passage that passes through the gap a, the hole 41 c, the gap c and the spline 63 b or 41 b having a portion where a tooth is partially cut, and a second oil passage that passes the gap b. The first oil passage is communicated with the front side surface of the one-way clutch 60, and with the housing 2 via the spline 30 having a cut portion or the spline 28 b and the thrust bearing 40. The resultant lubricating oil passage that includes the first and the second oil passages is communicated with the housing 2 of the clutch assembly 1 ₂ from the transmission case 45.

[0103] The sleeve shaft 41 connected to the inner race 63 of the one-way clutch 60 via the sleeve 63 a is connected to a predetermined element of the device for selecting the speed among the forward and reverse speeds in the continuously variable transmission. The one-way clutch 60 is structured to restrict the rotation opposite to the running direction in the forward or the reverse range selected by the vehicle operator. In the case where the D range as the forward range is selected, the one-way clutch 60 restricts the rotation in the reverse direction so as to prevent the vehicle that stops uphill from being moved backward. In the case where the reverse range is selected, the one-way clutch 60 restricts the forward direction so as to prevent the vehicle that stops downhill from being moved forward.

[0104] Referring to FIG. 4, further embodiment that has been partially modified will be described. The clutch assembly of the modified embodiment has the damper device that is substantially the same as that of the embodiment as shown in FIG. 1. However, as the input (drive) member and the output (driven) member are reversed in the modified embodiment, the connection of those members, thus, is different from that of the aforementioned embodiment. As other elements of the embodiment are substantially the same as those of the aforementioned embodiment, the main portions are designated as the same reference numerals. The description of those portions, thus, will be omitted.

[0105] The damper device 12 ₂ includes a drive plate 33 and a driven plate 31. The drive plate 33 corresponding to the driven plate in the aforementioned embodiment is formed of two plates disposed on the right and left outer sides for interposing the driven plate 31 corresponding to the drive plate in the aforementioned embodiment, which is disposed on the outer radial side. The intermediate plate 32, first spring 35 and the second spring 34, which are disposed in an intermediate position of the aforementioned power transmission system have the same functions.

[0106] The clutch hub 16 of the clutch 10 has a spline 16 a that brings the clutch discs 13 into engagement at the outer radial side. The spline 16 a further extends to form an integrated clutch hub member 16 b having a cylindrical hub 16 c formed on its end. An extending portion 33 a of the drive plate 33 is integrally fixed to the extending portion (input member) 16 b as the integrated member with the rivet 70 and the like.

[0107] The boss 30 serving as the output member has a cylindrical support portion (outer peripheral surface) 30 a formed on a front end, and a connecting portion 30 f as an extended rear end toward an outer radial direction. The end of the connecting portion 30 f is bent in the axial direction to form an edge portion (protrusion) 30 g. A connection plate 73 is fixed to be integrated with the connecting portion 30 f with the rivet 72. The connecting portion 30 f is engaged with a concave/convex portion 31 a of the driven plate 31 by a notch 73 a formed on the end of the connection plate 73. A thrust washer (latch member) 76 is fastened to the end of the support portion 30 a of the boss 30 with the snap ring (lock member) 75.

[0108] The hub portion 16 c of the clutch hub integrated member 16 b integrally combined with the drive plate (drive member) 33 is slidably supported on the support portion (outer peripheral surface) 30 a of the boss 30. One end of the hub portion 16 c abuts on the thrust washer 76, and the other end abuts on the tip of the edge portion 30 g of the boss 30. Accordingly, the integrated member 16 b is supported while being restricted with respect to the axial movement.

[0109] The torque from the clutch hub 16 is transmitted to the drive plate 33 in the damper device 12 ₂. The damper device 12 ₂ absorbs the impact caused by the engagement of the clutch 10 over a long stroke by means of two first springs 35 disposed in series on the inner radial side. The damper device 12 ₂ further absorbs the impact in the middle of the long stroke by means of the second spring 34 disposed on the outer radial side. The torque is, then, transmitted to the driven plate 31, and further to the boss 30 via the connection plate 73.

[0110] In each of the clutch assemblies 1 ₁, 1 ₂, and 1 ₃, the clutch 10 is engaged/disengaged for connecting engine outputs to the input shaft 28 of the automatic transmission so as to start the vehicle without using the torque converter (T/C). The resultant transmission efficiency can be improved by reducing slip between input and output members employed in the torque converter. The present clutch assembly has the oil chamber 23 formed by fitting the piston 20 of the clutch 10 oil tightly with the housing 2. Therefore, no leakage of oil from the oil chamber 23 to the housing 2 occurs, improving controllability of the clutch 10. The present clutch assembly has a simple structure that does not require the clutch case formed of the member other than the housing 2, which is employed for the clutch or the hydraulic actuator, thus improving reliability of the assembly. As each of the damper devices 12 ₁, 12 ₂ is aligned in the axial direction with the clutch 10 and the input shaft 28 (lateral direction of the drawings as shown in FIGS. 1, 2, and 4, respectively), the position of the damper spring may be freely determined in the radial direction (longitudinal direction of the drawings as shown in FIGS. 1, 2, and 4, respectively) of the damper devices 12 ₁, 12 ₂. This makes it possible to increase the degree of freedom in designing the damper devices 12 ₁ and 12 ₂.

[0111] The oil chamber 23 defined by the piston 20 and the housing 2 is disposed to be overlapped with the clutch plates 14 and the clutch discs 13 at the inner circumference thereof in the axial direction. As the clutch 10 and each of the damper devices 12 ₁, 12 ₂ are aligned in the axial direction, the length of the housing 2 in the axial direction is increased. However, such increase in the length can be kept to the minimum value.

[0112] The housing 2 includes a connecting portion formed of the lid member 55 connected to an engine crank shaft (not shown), a front cover (first housing member) 5 to which the connecting portion is fixed, and a second housing member formed of a center piece 3 connected to the front cover 5, a rear cover 6 and a rear hub 7. As the clutch plates 14 are fit with the spline 15 of the front cover 5, the engine output torque is not transmitted through the welded points (bonded points) j1, j2 between the first housing member 5 and the second housing member 3, 6, 7. As a result, the strength of the housing 2 formed of a plurality of members may be easily established.

[0113] The piston 20 is oil tightly fit with the center piece 3 or the like that forms the second housing member such that the clutch plates 14 and the clutch discs 13 are pressed upon supply of the oil pressure to the oil chamber 23 defined by the piston 20 and the center piece 3. That is, the portion at which the front cover 5 and the center piece 3 are bonded is not formed within the oil chamber 23. Therefore, even if a relatively higher oil pressure acts on the oil chamber 23, the leakage of the oil may be reliably prevented.

[0114] Each of the damper devices 12 ₁, 12 ₂ includes the drive plate 31, the driven plate 33, the first springs 35 that act between the drive plate 31 and the driven plate 33, and the second spring 34 that acts between the drive plate 31 and the driven plate 33 with a predetermined allowance. Then the drive plate 31 is connected to the clutch hub 16, and the driven plate 33 is connected to the boss 30. This makes it possible to align the clutch 10 and the damper device 12 ₁ or 12 ₂ in the axial direction even if the first and the second springs 35, 34 are disposed for providing the damper characteristics. Therefore, the increase in each size of the clutch assemblies 1 ₁, 1 ₂, 1 ₃ in the radial direction may be prevented.

INDUSTRIAL AVAILABILITY

[0115] The clutch assembly according to the present invention is useful as being employed for various types of vehicles having an internal combustion engine and an automatic transmission. It is preferable to apply the present invention especially to the clutch assembly that is demanded to have a simple structure and a high reliability. 

1. A clutch assembly including a clutch and a damper device housed in a housing that is connected to an engine output member, and an output member connected to an input shaft of an automatic transmission, the clutch assembly performing connection and disconnection of an output of an engine fed to the input shaft of the automatic transmission by engaging and disengaging the clutch, wherein: the clutch includes a first friction member, a second friction member, and a piston that is oil tightly fit with the housing so as to apply pressure to the first and the second friction members; and the damper device axially aligned with the clutch has one end connected to a clutch hub that supports the second friction member and the other end connected to the output member.
 2. The clutch assembly according to claim 1, further comprising an oil chamber formed between the piston and the housing so as to be overlapped with the first and the second friction members at a side of inner circumferences thereof in an axial direction.
 3. The clutch assembly according to claim 1, wherein: the housing includes a connecting portion connected to the engine output member, a first housing member to which the connecting portion is fixed, and a second housing member connected to the first housing member; and the first friction member is fit with a spline formed on the first housing member.
 4. The clutch assembly according to claim 3, wherein the piston is oil tightly fit with the second housing member for applying pressure to the first and the second friction members upon a supply of an oil pressure to the oil chamber formed between the piston and the second housing member.
 5. The clutch assembly according to claim 1, wherein: the damper device includes a drive plate, a driven plate, a first spring functions between the drive plate and the driven plate, and a second spring that functions between the drive plate and the driven plate with a predetermined allowance; and the drive plate is connected to the clutch hub and the driven plate is connected to the output member.
 6. The clutch assembly according to claim 5, wherein: the damper device further includes an intermediate plate; and the first spring functions in a serial manner between the drive plate and the intermediate plate, and between the intermediate plate and the driven plate.
 7. The clutch assembly according to claim 6, wherein the first spring is disposed at an inner radial side of the damper device with respect to the second spring.
 8. The clutch assembly according to claim 1, wherein: the input shaft of the transmission is engaged with an inner peripheral surface of the output member with a spline; a sleeve shaft is fit with the input shaft with a first gap so as to be fit with the output member oil tightly; a hub constituting the housing is oil tightly and rotatively supported on a transmission case of the transmission with a second gap formed on an outer radial side of the sleeve shaft; and the first gap and the second gap form a lubricating oil circulation passage in the housing.
 9. The clutch assembly according to claim 1 further comprising a one-way clutch fit into a concave portion formed on one side of the output member by fixing an outer race thereto, wherein: a sleeve is formed on an inner race of the one-way clutch; an input shaft of the transmission is engaged with an inner peripheral surface of the output member with a spline; a sleeve shaft is fit with the input shaft with a first gap, and the sleeve formed on the inner race is fit with the sleeve shaft so as to be engaged with a spline; a hub constituting the housing is oil tightly and rotatively supported on a transmission case of the transmission with a second gap formed on an outer radial side of the sleeve shaft and the sleeve; and a communication hole is formed on an end of the sleeve shaft such that the first gap and the second gap form a lubricating oil circulation passage in the housing.
 10. The clutch assembly according to claim 1, wherein: the housing includes a side surface, a hub, and a cylindrical portion which are integrated with the side surface thereof; an outer friction plate serving as the first friction member and an inner friction plate serving as the second friction member are engaged with a spline disposed on the inner peripheral side of the cylindrical portion and with a spline disposed on an outer peripheral surface of the clutch hub, respectively so as to form the clutch of a wet multiple disk type; an oil passage formed on the hub is communicated with an oil chamber defined by a side surface of the housing and the piston; and the piston serves to apply pressure to the clutch, and resultant counter force of the clutch is directly supported by the housing.
 11. The clutch assembly according to claim 10, wherein: the cylindrical portion comprises an intermediate cylindrical portion that is formed on an intermediate portion to the front of the housing in the radial direction; the side surface of the housing comprises a flat plate-like member that is disposed on an inner radial side of the intermediate cylindrical portion; and the damper device is stored in a large-diameter storage portion formed to the rear of the housing, and a hydraulic actuator formed of the clutch, the piston, and the oil chamber is disposed in a small-diameter storage portion, and formed on an inner radial side of the intermediate cylindrical portion to the front of the housing.
 12. The clutch assembly according to claim 10, wherein a retainer plate is fixed to the hub of the housing, and a return spring is disposed under pressure between the retainer plate and a back surface of the piston.
 13. The clutch assembly according to claim 10, wherein the spline used for engaging the outer friction plate of the clutch is directly formed on an inner peripheral surface of the cylindrical portion in the housing.
 14. The clutch assembly according to claim 10, wherein: a concave portion is formed on an end surface of the hub of the housing such that the input shaft of the transmission is oil tightly fit with the concave portion; and an oil hole that extends in an axial direction is formed in the input shaft, and an end opening of the oil hole is communicated with the oil passage formed in the hub.
 15. The clutch assembly according to claim 10, wherein: the piston has an operating portion that extends toward an outer radial direction such that the clutch is operated; and the operating portion abuts on an inner surface of the housing upon disengagement of the clutch, and has an outer circumference engaged with a spline on an inner peripheral side of the cylindrical portion.
 16. The clutch assembly according to claim 1, wherein: the clutch includes at least one friction plate comprising the first friction member that is engaged with a spline for rotating integrally with the housing, and at least one inner friction plate comprising the second friction member that is engaged with a spline formed on a clutch hub, which are alternately disposed; the damper device includes a drive member, a driven member, and a spring disposed on a power transmission path from the drive member to the driven member; the damper device further includes a boss serving as the output member connected to the driven member, and an input member integrally combined with the clutch hub and connected to the drive member; and an inner peripheral surface of the input member is slidably supported directly on an outer peripheral surface of the boss in a rotating direction while being restricted with respect to an axial movement.
 17. The clutch assembly according to claim 16, wherein: the input member has a cylindrical hub portion on an inner peripheral surface thereof; the boss includes a cylindrical support portion that supports the hub portion, a protruding portion formed on one end of the support portion in an axial direction and, protruding toward an outer radial direction, and a restricting member formed on the other end of the support portion in the axial direction and, protruding toward an outer radial direction of the support portion while being restricted with respect to at least a movement in the axial direction; and the input member is slidably supported on the support portion of the boss and interposed between the protruding portion and the restricting member so as to be restricted with respect to the movement in the axial direction.
 18. The clutch assembly according to claim 17, wherein the protruding portion of the boss comprises a collar portion integrally formed with the cylindrical support portion, and the restricting member comprises an extending portion of the driven member fixed at the boss.
 19. The clutch assembly according to claim 18, wherein the input member comprises a connection plate that serves to fix the clutch hub, extends in a radial direction to be connected to the drive member on an outer radial portion thereof, and forms the hub portion on an inner radial portion thereof.
 20. The clutch assembly according to claim 17, wherein: the driven member comprises two driven plates that interpose the drive member and the spring; at least one of the two driven plates is fixed to the boss; and an inner peripheral surface of the drive member is slidably supported directly on an outer peripheral surface of a ring portion integrally formed with the boss.
 21. The clutch assembly according to claim 20, wherein: the damper device comprises a drive plate, an intermediate plate, a driven plate, a first spring functioning in a serial manner between the drive plate and the intermediate plate, and between the intermediate plate and the driven plate, respectively, and a second spring functioning between the drive plate and the driven plate with a predetermined allowance; and the drive plate comprises the drive member connected to the input member, and the intermediate plate comprises the drive member supported on the ring portion.
 22. The clutch assembly according to claim 21, wherein the ring portion is formed on an outer race of a one-way clutch disposed in a concave portion of the boss so as to protrude toward an outer radial direction.
 23. The clutch assembly according to claim 17, wherein the protruding portion of the boss comprises a connecting portion of the driven member integrally formed with the boss, and the restricting member comprises a lock member that is fixed to the support portion.
 24. The clutch assembly according to claim 23, wherein the input member comprises a clutch hub integrated member that is integrally formed with the clutch hub, and connected to the drive member on an inner radial portion so as to form the hub portion.
 25. The clutch assembly according to claim 24, wherein: the drive member comprises two drive plates that interpose the driven member and the spring; one of the two drive plates which locates at the clutch hub is fixed to the clutch hub integrated member; a connection plate that extends toward a radial direction is provided so as to connect the driven member and the boss; and an inner peripheral surface of the drive member is slidably supported on an outer peripheral surface of the ring portion integrally combined with the boss.
 26. The clutch assembly according to claim 25, wherein: the damper device comprises a drive plate, an intermediate plate, a driven plate, a first spring functioning in a serial manner between the drive plate and the intermediate plate, and between the intermediate plate and the driven plate, respectively, and a second spring functioning between the drive plate and the driven plate with a predetermined allowance; and the drive plate comprises the drive member connected to the input member, and the intermediate plate comprises the drive member supported on the ring portion.
 27. The clutch assembly according to claim 26, wherein the ring portion is formed on an outer race of a one-way clutch disposed in a concave portion of the boss so as to protrude toward an outer radial direction.
 28. The clutch assembly according to claim 16, wherein: the housing has a large-diameter storage portion on one side, and a small-diameter storage portion on the other side; and the large-diameter storage portion stores the damper device and the input member, and the small-diameter storage portion stores the clutch and a hydraulic actuator.
 29. A clutch assembly including a clutch and a damper device housed in a housing that is connected to an engine output member, and an output member connected to an input shaft of an automatic transmission and having both sides directly supported on the housing via a bearing, and a take-off controller that transmits an output of the engine to the automatic transmission by engaging the clutch so as to start a vehicle, wherein: the damper device includes a drive plate connected to an output member of the clutch, a driven plate connected to the output member, a first spring functioning in a serial manner between the drive plate and the driven plate, and a second spring functioning between the drive plate and the driven plate with a predetermined allowance, and the first spring is disposed at an inner radial side of the damper device with respect to the second spring; and the damper device including the first and the second spring arranged in the radial direction is aligned with the clutch in an axial direction. 